Can blood test concerning Down syndrome be wrong during pregnancy?

Answer 1

Yes. Quite commonly Down syndrome is diagnosed or highly suspected before birth. Prenatal ultrasound can be used to increase the suspicion of Down syndrome by evaluating the nuchal lucency during the 1st trimester. The triple screen (HCG, AFP, and estriol) can also point to a potential chromosomal abnormality. An amniocentesis or chorionic villus sampling can clinch the diagnosis by allowing prenatal chromosomal analysis.

Answer 2

A lot of women experience the possibility of down's syndrome due to some tests performed during pregnancy. If your doctor says there is a possibility of down's syndrome than don't panic just yet but if your doctor has confirmed down's syndrome then I would start preparing yourself, as well as your husband. Your might consider having an amnio or CVS done for further testing. The way down's syndrome is diagnosed through a blood sample is the chromosomes are tested. If Down's Syndrome is present, the fetus will have 3 number 21 chromosomes instead of two. But from a blood test, just your blood is tested, although it can still be accurate, I would recommend having an amnio or CVS for a better prediction.

Answer 3

It is a personal decision to have blood work done during pregnancy to determine the risks that the baby will have Trisomy 21 (Downs Syndrome). First trimester screening can be done or the mother can have the quad screen test in the second trimester. Blood work does not determine whether or not the baby will have Downs - it gives the chance. For example, a positive test would indicate that the baby has a 1:147 chance of having Downs. There are cases where a mother had a 1:1000 chance that her baby would have Downs and then the baby was born with Downs.

If a mother wants to know whether or not the baby will be born with Downs, she would need to have an amniocentesis done where the baby's chromosomes would be counted and if the baby had an extra #21 chromosome, that would mean that the baby would be born with Downs. Couples may choose to have the blood work done to see if they have a higher than normal risk. If they have this positive test, then their doctor may encourage them to have an amniocentesis. Knowing that your baby has Downs Syndrome in advance of the birth may allow the parents to have the additional resources in place. Many women do not find out in advance and seek the additional care once the baby is born.